1. Technical Field
The present invention relates to a plasma display panel, and more particularly, to a plasma display panel with a reduced voltage drop over the sustain electrodes and scanning electrodes.
2. Discussion of Related Technologies
In general, a plasma display panel (hereinafter, referred to as a “PDP”) displays images using a plasma generated by an electrical discharge within a suitable gas. A PDP typically has good display characteristics, such as a high resolution, high brightness, high contrast, a reduction in residual images (ghosting), and a wide viewing angle.
Typically, a front substrate having sustain electrodes and scanning electrodes formed thereon is bonded to a rear substrate having address electrodes formed thereon. Barrier ribs interposed between the front and rear substrates form a plurality of discharge cells, which are typically filled with an inert gas suitable for generating a plasma, for example, a mixture of neon (Ne) and xenon (Xe).
An address discharge in a discharge cell occurs when an address voltage is applied to the address electrode and scanning pulses are applied to the scanning electrode, thereby forming wall charges between the two electrodes, and selecting a discharge cell to-be-turned-on.
When sustain pulses are applied to the sustain electrodes and the scanning electrodes after an address discharge, electrons and ions formed on the sustain electrodes and the scanning electrodes move between the sustain electrodes and the scanning electrodes, thereby generating a voltage therebetween. As a result, when the sum of the voltage generated by the electrons and ions and the wall voltage generated by the address discharge is larger than a breakdown voltage, a sustain discharge occurs in the selected discharge cells.
Subsequently, vacuum ultraviolet rays generated in the discharge cells by the sustain discharge excite a phosphor layer. The electronically excited phosphor layer relaxes to a lower energy state, thereby emitting visible light, thereby forming the images displayed on the PDP.
Typically, each of the sustain electrodes and the scanning electrodes comprises a transparent electrode, which generates the sustain discharge in the discharge cell, and a bus electrode, which applies a voltage to the transparent electrode.
The bus electrode is generally a highly conductive metallic material, which is opaque. Therefore, in order to reduce shielding of visible light generated by the discharge cells, the bus electrode is typically formed above a barrier rib, which is a non-discharge region.
However, the sustain electrodes and the scanning electrodes each comprise a transparent electrode, which typically has a lower conductivity than the bus electrode. Therefore, a large voltage drop occurs across the transparent electrode, between a back end proximal to the bus electrode, and a front end distal to the bus electrode and near the center of the discharge cell. This voltage drop also increases the time required for generating an address discharge light.
As the size of a PDP increases, the length of each bus electrode also increases. A longer bus electrode translates into an increased voltage drop over the length of the bus electrode. Therefore, the overall voltage drop at the front end of the transparent electrode also increases with increasing display size.
Consequently, the related art exhibits at least two problems: higher voltages required to achieve a sustain discharge because of the voltage drops over the transparent electrodes and bus electrodes, and extended times required for generating an address discharge.